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1 | ;;; tls.el --- TLS/SSL support via wrapper around GnuTLS |
2 | ||
3c5fa30a GM |
3 | ;; Copyright (C) 1996, 1997, 1998, 1999, 2002, 2003, 2004, 2005, 2006, |
4 | ;; 2007, 2008 Free Software Foundation, Inc. | |
01b2d1dd SJ |
5 | |
6 | ;; Author: Simon Josefsson <simon@josefsson.org> | |
7 | ;; Keywords: comm, tls, gnutls, ssl | |
8 | ||
9 | ;; This file is part of GNU Emacs. | |
10 | ||
874a927a | 11 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
01b2d1dd | 12 | ;; it under the terms of the GNU General Public License as published by |
874a927a GM |
13 | ;; the Free Software Foundation, either version 3 of the License, or |
14 | ;; (at your option) any later version. | |
01b2d1dd SJ |
15 | |
16 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
874a927a | 18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
01b2d1dd SJ |
19 | ;; GNU General Public License for more details. |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
874a927a | 22 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
01b2d1dd SJ |
23 | |
24 | ;;; Commentary: | |
25 | ||
26 | ;; This package implements a simple wrapper around "gnutls-cli" to | |
27 | ;; make Emacs support TLS/SSL. | |
28 | ;; | |
29 | ;; Usage is the same as `open-network-stream', i.e.: | |
30 | ;; | |
31 | ;; (setq tmp (open-tls-stream "test" (current-buffer) "news.mozilla.org" 563)) | |
32 | ;; ... | |
33 | ;; #<process test> | |
34 | ;; (process-send-string tmp "mode reader\n") | |
35 | ;; 200 secnews.netscape.com Netscape-Collabra/3.52 03615 NNRP ready ... | |
36 | ;; nil | |
37 | ;; (process-send-string tmp "quit\n") | |
38 | ;; 205 | |
39 | ;; nil | |
40 | ||
41 | ;; To use this package as a replacement for ssl.el by William M. Perry | |
42 | ;; <wmperry@cs.indiana.edu>, you need to evaluate the following: | |
43 | ;; | |
44 | ;; (defalias 'open-ssl-stream 'open-tls-stream) | |
45 | ||
46 | ;;; Code: | |
47 | ||
3c5fa30a GM |
48 | (autoload 'format-spec "format-spec") |
49 | (autoload 'format-spec-make "format-spec") | |
01b2d1dd SJ |
50 | |
51 | (defgroup tls nil | |
52 | "Transport Layer Security (TLS) parameters." | |
53 | :group 'comm) | |
54 | ||
59c95dc2 | 55 | (defcustom tls-end-of-info |
cd6db47c GM |
56 | (concat |
57 | "\\(" | |
58 | ;; `openssl s_client' regexp. See ssl/ssl_txt.c lines 219-220. | |
59 | ;; According to apps/s_client.c line 1515 `---' is always the last | |
60 | ;; line that is printed by s_client before the real data. | |
61 | "^ Verify return code: .+\n---\n\\|" | |
62 | ;; `gnutls' regexp. See src/cli.c lines 721-. | |
63 | "^- Simple Client Mode:\n" | |
64 | "\\(\n\\|" ; ignore blank lines | |
2cddada0 | 65 | ;; According to GnuTLS v2.1.5 src/cli.c lines 640-650 and 705-715 |
7b63c073 | 66 | ;; in `main' the handshake will start after this message. If the |
2cddada0 | 67 | ;; handshake fails, the programs will abort. |
cd6db47c GM |
68 | "^\\*\\*\\* Starting TLS handshake\n\\)*" |
69 | "\\)") | |
59c95dc2 GM |
70 | "Regexp matching end of TLS client informational messages. |
71 | Client data stream begins after the last character matched by | |
72 | this. The default matches `openssl s_client' (version 0.9.8c) | |
73 | and `gnutls-cli' (version 2.0.1) output." | |
74 | :version "22.2" | |
75 | :type 'regexp | |
76 | :group 'tls) | |
77 | ||
01b2d1dd | 78 | (defcustom tls-program '("gnutls-cli -p %p %h" |
3031d8b0 | 79 | "gnutls-cli -p %p %h --protocols ssl3" |
d55fe5bb | 80 | "openssl s_client -connect %h:%p -no_ssl2 -ign_eof") |
01b2d1dd SJ |
81 | "List of strings containing commands to start TLS stream to a host. |
82 | Each entry in the list is tried until a connection is successful. | |
4a3c7686 | 83 | %h is replaced with server hostname, %p with port to connect to. |
01b2d1dd | 84 | The program should read input on stdin and write output to |
b890d447 MB |
85 | stdout. |
86 | ||
87 | See `tls-checktrust' on how to check trusted root certs. | |
88 | ||
89 | Also see `tls-success' for what the program should output after | |
90 | successful negotiation." | |
91 | :type | |
92 | '(choice | |
93 | (list :tag "Choose commands" | |
94 | :value | |
95 | ("gnutls-cli -p %p %h" | |
96 | "gnutls-cli -p %p %h --protocols ssl3" | |
d55fe5bb | 97 | "openssl s_client -connect %h:%p -no_ssl2 -ign_eof") |
b890d447 MB |
98 | (set :inline t |
99 | ;; FIXME: add brief `:tag "..."' descriptions. | |
100 | ;; (repeat :inline t :tag "Other" (string)) | |
101 | ;; See `tls-checktrust': | |
102 | (const "gnutls-cli --x509cafile /etc/ssl/certs/ca-certificates.crt -p %p %h") | |
103 | (const "gnutls-cli --x509cafile /etc/ssl/certs/ca-certificates.crt -p %p %h --protocols ssl3") | |
d55fe5bb | 104 | (const "openssl s_client -connect %h:%p -CAfile /etc/ssl/certs/ca-certificates.crt -no_ssl2 -ign_eof") |
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105 | ;; No trust check: |
106 | (const "gnutls-cli -p %p %h") | |
107 | (const "gnutls-cli -p %p %h --protocols ssl3") | |
d55fe5bb | 108 | (const "openssl s_client -connect %h:%p -no_ssl2 -ign_eof")) |
b890d447 MB |
109 | (repeat :inline t :tag "Other" (string))) |
110 | (const :tag "Default list of commands" | |
111 | ("gnutls-cli -p %p %h" | |
112 | "gnutls-cli -p %p %h --protocols ssl3" | |
d55fe5bb | 113 | "openssl s_client -connect %h:%p -no_ssl2 -ign_eof")) |
b890d447 MB |
114 | (list :tag "List of commands" |
115 | (repeat :tag "Command" (string)))) | |
3031d8b0 | 116 | :version "22.1" |
01b2d1dd SJ |
117 | :group 'tls) |
118 | ||
119 | (defcustom tls-process-connection-type nil | |
b890d447 | 120 | "Value for `process-connection-type' to use when starting TLS process." |
bf247b6e | 121 | :version "22.1" |
01b2d1dd SJ |
122 | :type 'boolean |
123 | :group 'tls) | |
124 | ||
3031d8b0 | 125 | (defcustom tls-success "- Handshake was completed\\|SSL handshake has read " |
b890d447 | 126 | "Regular expression indicating completed TLS handshakes. |
3031d8b0 MB |
127 | The default is what GNUTLS's \"gnutls-cli\" or OpenSSL's |
128 | \"openssl s_client\" outputs." | |
bf247b6e | 129 | :version "22.1" |
01b2d1dd SJ |
130 | :type 'regexp |
131 | :group 'tls) | |
132 | ||
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133 | (defcustom tls-checktrust nil |
134 | "Indicate if certificates should be checked against trusted root certs. | |
135 | If this is `ask', the user can decide whether to accept an | |
136 | untrusted certificate. You may have to adapt `tls-program' in | |
137 | order to make this feature work properly, i.e., to ensure that | |
138 | the external program knows about the root certificates you | |
139 | consider trustworthy, e.g.: | |
140 | ||
141 | \(setq tls-program | |
142 | '(\"gnutls-cli --x509cafile /etc/ssl/certs/ca-certificates.crt -p %p %h\" | |
143 | \"gnutls-cli --x509cafile /etc/ssl/certs/ca-certificates.crt -p %p %h --protocols ssl3\" | |
d55fe5bb | 144 | \"openssl s_client -connect %h:%p -CAfile /etc/ssl/certs/ca-certificates.crt -no_ssl2 -ign_eof\"))" |
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145 | :type '(choice (const :tag "Always" t) |
146 | (const :tag "Never" nil) | |
147 | (const :tag "Ask" ask)) | |
dd22fbf6 | 148 | :version "23.1" ;; No Gnus |
b890d447 MB |
149 | :group 'tls) |
150 | ||
151 | (defcustom tls-untrusted | |
152 | "- Peer's certificate is NOT trusted\\|Verify return code: \\([^0] \\|.[^ ]\\)" | |
153 | "Regular expression indicating failure of TLS certificate verification. | |
154 | The default is what GNUTLS's \"gnutls-cli\" or OpenSSL's | |
155 | \"openssl s_client\" return in the event of unsuccessful | |
156 | verification." | |
157 | :type 'regexp | |
dd22fbf6 | 158 | :version "23.1" ;; No Gnus |
b890d447 MB |
159 | :group 'tls) |
160 | ||
161 | (defcustom tls-hostmismatch | |
162 | "# The hostname in the certificate does NOT match" | |
163 | "Regular expression indicating a host name mismatch in certificate. | |
164 | When the host name specified in the certificate doesn't match the | |
165 | name of the host you are connecting to, gnutls-cli issues a | |
166 | warning to this effect. There is no such feature in openssl. Set | |
167 | this to nil if you want to ignore host name mismatches." | |
168 | :type 'regexp | |
dd22fbf6 | 169 | :version "23.1" ;; No Gnus |
b890d447 MB |
170 | :group 'tls) |
171 | ||
18965008 SJ |
172 | (defcustom tls-certtool-program (executable-find "certtool") |
173 | "Name of GnuTLS certtool. | |
174 | Used by `tls-certificate-information'." | |
bf247b6e | 175 | :version "22.1" |
9bdd0e16 | 176 | :type 'string |
18965008 SJ |
177 | :group 'tls) |
178 | ||
179 | (defun tls-certificate-information (der) | |
180 | "Parse X.509 certificate in DER format into an assoc list." | |
181 | (let ((certificate (concat "-----BEGIN CERTIFICATE-----\n" | |
182 | (base64-encode-string der) | |
183 | "\n-----END CERTIFICATE-----\n")) | |
184 | (exit-code 0)) | |
185 | (with-current-buffer (get-buffer-create " *certtool*") | |
186 | (erase-buffer) | |
187 | (insert certificate) | |
188 | (setq exit-code (condition-case () | |
189 | (call-process-region (point-min) (point-max) | |
190 | tls-certtool-program | |
191 | t (list (current-buffer) nil) t | |
192 | "--certificate-info") | |
193 | (error -1))) | |
194 | (if (/= exit-code 0) | |
195 | nil | |
196 | (let ((vals nil)) | |
197 | (goto-char (point-min)) | |
198 | (while (re-search-forward "^\\([^:]+\\): \\(.*\\)" nil t) | |
199 | (push (cons (match-string 1) (match-string 2)) vals)) | |
200 | (nreverse vals)))))) | |
201 | ||
3031d8b0 MB |
202 | (defun open-tls-stream (name buffer host port) |
203 | "Open a TLS connection for a port to a host. | |
01b2d1dd SJ |
204 | Returns a subprocess-object to represent the connection. |
205 | Input and output work as for subprocesses; `delete-process' closes it. | |
3031d8b0 | 206 | Args are NAME BUFFER HOST PORT. |
01b2d1dd | 207 | NAME is name for process. It is modified if necessary to make it unique. |
b890d447 | 208 | BUFFER is the buffer (or buffer name) to associate with the process. |
01b2d1dd SJ |
209 | Process output goes at end of that buffer, unless you specify |
210 | an output stream or filter function to handle the output. | |
211 | BUFFER may be also nil, meaning that this process is not associated | |
212 | with any buffer | |
213 | Third arg is name of the host to connect to, or its IP address. | |
3031d8b0 | 214 | Fourth arg PORT is an integer specifying a port to connect to." |
0ad32c54 CY |
215 | (let ((cmds tls-program) |
216 | (use-temp-buffer (null buffer)) | |
217 | process cmd done) | |
218 | (if use-temp-buffer | |
3c2dbd94 KY |
219 | (setq buffer (generate-new-buffer " TLS")) |
220 | ;; BUFFER is a string but does not exist as a buffer object. | |
221 | (unless (and (get-buffer buffer) | |
222 | (buffer-name (get-buffer buffer))) | |
223 | (generate-new-buffer buffer))) | |
cd6db47c | 224 | (with-current-buffer buffer |
59c95dc2 GM |
225 | (message "Opening TLS connection to `%s'..." host) |
226 | (while (and (not done) (setq cmd (pop cmds))) | |
227 | (message "Opening TLS connection with `%s'..." cmd) | |
228 | (let ((process-connection-type tls-process-connection-type) | |
229 | response) | |
230 | (setq process (start-process | |
231 | name buffer shell-file-name shell-command-switch | |
232 | (format-spec | |
233 | cmd | |
234 | (format-spec-make | |
235 | ?h host | |
236 | ?p (if (integerp port) | |
237 | (int-to-string port) | |
238 | port))))) | |
239 | (while (and process | |
240 | (memq (process-status process) '(open run)) | |
241 | (progn | |
242 | (goto-char (point-min)) | |
0a4d4654 GM |
243 | (not (setq done (re-search-forward |
244 | tls-success nil t))))) | |
59c95dc2 GM |
245 | (unless (accept-process-output process 1) |
246 | (sit-for 1))) | |
247 | (message "Opening TLS connection with `%s'...%s" cmd | |
248 | (if done "done" "failed")) | |
0a4d4654 GM |
249 | (if (not done) |
250 | (delete-process process) | |
251 | ;; advance point to after all informational messages that | |
252 | ;; `openssl s_client' and `gnutls' print | |
253 | (let ((start-of-data nil)) | |
254 | (while | |
ea666a77 RS |
255 | (not (setq start-of-data |
256 | ;; the string matching `tls-end-of-info' | |
257 | ;; might come in separate chunks from | |
258 | ;; `accept-process-output', so start the | |
259 | ;; search where `tls-success' ended | |
260 | (save-excursion | |
261 | (if (re-search-forward tls-end-of-info nil t) | |
262 | (match-end 0))))) | |
0a4d4654 GM |
263 | (accept-process-output process 1)) |
264 | (if start-of-data | |
265 | ;; move point to start of client data | |
266 | (goto-char start-of-data))) | |
ea666a77 | 267 | (setq done process)))) |
0a4d4654 GM |
268 | (when (and done |
269 | (or | |
270 | (and tls-checktrust | |
271 | (save-excursion | |
272 | (goto-char (point-min)) | |
273 | (re-search-forward tls-untrusted nil t)) | |
274 | (or | |
275 | (and (not (eq tls-checktrust 'ask)) | |
276 | (message "The certificate presented by `%s' is \ | |
277 | NOT trusted." host)) | |
278 | (not (yes-or-no-p | |
279 | (format "The certificate presented by `%s' is \ | |
280 | NOT trusted. Accept anyway? " host))))) | |
281 | (and tls-hostmismatch | |
282 | (save-excursion | |
283 | (goto-char (point-min)) | |
284 | (re-search-forward tls-hostmismatch nil t)) | |
285 | (not (yes-or-no-p | |
286 | (format "Host name in certificate doesn't \ | |
287 | match `%s'. Connect anyway? " host)))))) | |
288 | (setq done nil) | |
289 | (delete-process process))) | |
290 | (message "Opening TLS connection to `%s'...%s" | |
291 | host (if done "done" "failed")) | |
0ad32c54 | 292 | (when use-temp-buffer |
b7131d2f | 293 | (if done (set-process-buffer process nil)) |
0ad32c54 | 294 | (kill-buffer buffer)) |
01b2d1dd SJ |
295 | done)) |
296 | ||
297 | (provide 'tls) | |
298 | ||
cbee283d | 299 | ;; arch-tag: 5596d1c4-facc-4bc4-94a9-9863b928d7ac |
01b2d1dd | 300 | ;;; tls.el ends here |